6.6 Waves

Question 1

Amplitude

Answer 1

The maximum displacement of a wave from its undisturbed
(equilibrium) position

Question 2

Angle of Incidence

Answer 2

The angle between the incident ray and normal

Question 3

Angle of Reflection

Answer 3

The angle between the reflected ray and normal

Question 4

Black

Answer 4

An object will appear black if it absorbs all wavelengths of radiation incident on it

Question 5

Colour Filters

Answer 5

Filters that absorb certain wavelengths (colours) and transmit
others

A blue filter for example will absorb all wavelengths other than those in the blue region of the colour spectrum

Question 6

Colour

Answer 6

Colour is determined by frequency and wavelength

Question 7

Convex Lens

Answer 7

A lens that brings parallel rays to focus at the principal focus

The image formed can be either real or virtual

Question 8

Diffuse Reflection

Answer 8

Reflection from a rough surface that results in scattering

Question 9

Electromagnetic Waves

Answer 9

Transverse waves that transfer energy from the source
of the waves, to an absorber

They form a continuous spectrum of different frequencies and all travel at the same speed in a vacuum

Question 10

Focal Length

Answer 10

The distance between the centre of a lens and its principal focus

Question 11

Frequency

Answer 11

The number of waves passing a given point in a second

It is the inverse of the wave’s period

Question 12

Hertz

Answer 12

The unit of frequency

Question 13

Infrared Radiation

Answer 13

A type of radiation that all objects emit and absorb

The hotter an object is, the greater the infrared radiation it emits in a given time

Question 14

Infrared

Answer 14

Used for cooking food, electrical heaters and infrared imaging

Question 15

Ionising Radiation

Answer 15

Radiation that can cause the mutation of genes and cause
cancer

X-rays and gamma rays are both forms of ionising radiation

Question 16

Lens

Answer 16

An object that forms an image through the refraction of light

Question 17

Longitudinal Waves

Answer 17

Waves with oscillations that are parallel to the direction of
travel/energy transfer

Question 18

Magnification

Answer 18

The ratio of the image height over the object height for a lens

Since it is a ratio, it has no units

Question 19

Microwaves

Answer 19

Used for satellite communications and for cooking food

Question 20

Normal

Answer 20

The normal is an imaginary reference line that is constructed
perpendicular to a boundary at the point that the wave intercepts it

Question 21

Period

Answer 21

The time it takes for one complete wave to pass a given point

It is the inverse of frequency

Question 22

Radiation Dose

Answer 22

A measure of the risk of harm to the body as a result of radiation
exposure

Question 23

Radio Waves

Answer 23

Used for television and radio signals

They can be produced by oscillations in electrical circuits

Question 24

Specular Reflection

Answer 24

Reflection from a smooth surface, in a single direction

Question 25

Transverse Waves

Answer 25

Waves with oscillations that are perpendicular to the direction of travel/energy transfer

Question 26

Ultraviolet

Answer 26

Used in energy efficient lamps and for sun tanning

Question 27

Visible Light

Answer 27

The only type of electromagnetic radiation that our eyes can detect It is used for fibre optic communications

Question 28

Wave Speed

Answer 28

The speed at which energy is transferred through the medium It is equal to the product of the wave’s wavelength and frequency

Question 29

Wavelength

Answer 29

The distance from a point on one wave to the same point on the adjacent wave (ie. peak to peak or trough to trough).

Question 30

White

Answer 30

An object will appear white if it emits all wavelengths equally